Punching machine

ABSTRACT

A punching machine has a C-frame, which thus has a lower diesupporting arm, and an upper arm to which is detachably secured a module, removable as a unit, which module includes a rigid head which supports a ram, a toggle linkage secured to the head and ram, and a hydraulic actuator secured to the head and toggle linkage. A key between the head and upper arm serves to locate the module and to transfer reactive thrust therebetween.

United States Patent Kr n tzk et al. 1 A r.18 1972 [54] PUNCHING MACHINE 986,809 3/1933 Derbyshire et a1 ..83/639 X [72] Inventors: Alexander Krynytzky, West Seneca, N.Y.; Arthur Schm, Greensboro! -F 2,851,888 9/1958 Scholin .83/630 x Hoffmann, Tonawanda Townshlp, Erle 3,227,022 1/1966 Evans et al ...83/698 x NY. 2,532,672 12/1950 Michael et a1. ..83/630 X [73] Assrgnee: Houda1llelndustr1es,lnc., Buffalo, NY. Primary Examiner james M. Meister [22] Filed: May 25, 1970 Attorney-Hill, Sherman, Meroni, Gross and Simpson [21] AppLNQI 41,142 57 ABSTRACT Related U.S. Application Data A punching machine has a C-frame, which thus has a lower die-supporting arm, and an upper arm to which is detachably [62] Dlvlslon of 1966 securedamodule, removable as a unit, which module includes 3,529,502 a rigid head which supports a ram, a toggle linkage secured to [52] U.S.Cl ..83/530,83/630,83/639, the head and r m, n a hy raulic actuator secured to the 33/ 93 head and toggle linkage. A key between the head and upper 51 1111. C1. ..B26d 5/12, B26d 5/18 arm Serves locate the module and transfer reactive thrust [58] Field of Search ..83/530, 630, 698, 639,563, therebetween' 83/902, 916 '[56] References Cited UNlT ED STATES PATENTS 6 Claims, 2 Drawing Figures 486,387 11/1892 Snaith .83/630 PATENTEDAPR 18 m2 SHLET 2 BF 2 lnlmlliim BY 9 m application for U.S. PATENT ON A 1 PUNCHINGMACHINE This applicationis a'divisional application of our copending Punching Machine," filed Nov. 14, I966, Ser. No. 596,384, now U. S. Pat. No. 3,529,502.

Thepresent invention relatesto a heavy duty punch press of the 'C-frame type wherein the ramand its actuating means form part of a module secured to the upper arm of the C- fframe.

Accordingly, it is an object of the present invention to pro- -vide a heavy duty punching machine.

A further object of the present invention is to provide a power head assembly for reciprocating a tool, which power head assembly comprises a structural unit or module.

A still further object of the present invention is to provide means for reciprocating a punch tool while avoiding lengthy drive structures, suchmeans being able to be inched or jogged in small increments ifdesired.

A still further object of the presentinvention is to provide structureinthe module .for positively stripping a workpiece from thepunch of a high tonnage rating.

Yet another object of the present invention is to provide a punching machine module wherein the amount of space between the punch and the die when the punch is retracted can be adjusted.

Many other features, advantages and additionalobjects of the present invention willbecome manifest to those versed in the art upon making reference to the detailed description and to the accompanying sheets of drawings in which a preferred structural embodiment incorporating the principles of 'the present invention is shown by way of illustrative example.

ON THE DRAWINGS FIG. 1 is a cross-sectional view taken in a vertical plane throughthe upper part or operating head of a punching machine provided as.a module in accordance with the principlesof the present invention; and

FIG. 2 is a cross-sectional view, partly in elevation, taken generally along lineII-ll of FIG. 1.

AS SHOWN ON THE DRAWINGS:

The principles of this invention are particularly useful when embodied in a punching machine such as is fragmentarily illustrated .in FIG. 1, generally indicated by the numeral 10. The punching machine includes a rigid frame 11 which, when viewed from the side, is of C-shaped configuration having an upper ,arm 12 and a lower arm (not shown) rigidly secured thereto which supports a lower fixed tool, here comprising a die tool 13. The upper arm 12 supports a power head assembly constructed as a detachable module which includes a detachable head 14, which in turn slidably supports a' ram 15, a removable upper tool holder 16, at least one and preferably a pair of clamping actuators 17, 17, a toggle linkage 18, a fiuid actuator 19, and a pair of electrical switches 20, 21.

The ram 15 supports an upper movable tool, here comprising a punch tool 22 for coacting with the die 13 on a workpiece 23. The removable upper tool holder 16 supports a hold down member 24.

The frame 1 1 has a forwardly directed face 25 against which the detachable head 14 is secured as by a number of screws 26, which are externally accessible through frame apertures, proper registration and reactive thrust being obtained by means of a vertically close-fitting key 27 acting between the upper arm 12 and the detachable head 14.

' The ram 15 is slidably guided for vertical movement within. the head 14 and includes a pair of cars 28, 28, each of which is provided with an opening 29 which extends parallel to the direction of ram reciprocation. At its lower end, the ram 15 is provided with an adapter 30 which directly supports a head or driver 31 of the punch tool 22. In this embodiment, the adapter 30 and the punch head 31 are provided with a positive connection therebetween in the form of a horizontally extending T-slot 32 and a T-head '33 received'therein, best seen in FIG. 2. The adapter 30 is secured'by a number of screws 34, 34 and thus maybe readily replaced if desired.

The removable upper tool holder 16 is substantially the same as that shown in U. S. Pat. No. 3,225,636 to which any interested reader is referred for further structural information. As explained in that patent, the tool holder 16 hereof, which is only fragmentarily illustrated, may be manually released by actuation of means not shown here and moved toward the viewer as seen in FIG. 2. Altematively,either the left or the right side alone may be moved toward the viewer and thereby swung about the other side. The direction in which the horizontal T-shot 32 extends is such as to freely engage and disengage the positive connection 32, 33 in response to horizontal removal or attachment of the upper tool holder 16.

If desired, other tool holders maybe attached in place of the tool holder 16, for example tool holders of the type disclosed inthe aforementioned patent.

The clamping actuators 17 respectively include a hollow cylinder 35'which comprises'a cavity in the lower end of the detachable head 14, a piston 36, and a tubular rod 37 having a shoulder 38. The piston 36 is engaged by suitable seals of any known type acting between the piston 36 and the hollow cylinder 35. Similarly, the tubular rod 37 is engaged by other seals to prevent fluid leakage along the length of the rod 37. The interior of the tubular rod'37 communicates through porting in the piston 36 with the interior of the hollow cylinder 35, which has no fluid port of itself. Thus, fluid pressure may be applied through the tubular rod 37 to act on one end, here the upper end, of the piston 36. The piston 36 includes means at one side, here the lower side,-to act on the hold down member 24. In this-embodiment, such means merely comprises a pushing surface, which may be of any convenient configuration. At the other side of the piston 36, means are provided to deliver power to the piston 36 from the ram for retraction of the piston 36. Such means comprises the tubular rod 37, the upper end of which not only is fluidly connected to the supply of pressurized fluid, but whichsupports a shoulder 38, here comprising an adjustably located pair of lock nuts.

The toggle linkage vl8is pivotally supported at its upper end by an upper pivotpin 40 carried by the head 14, while the ram 15 has a pivotal connection with a lower'pivot pin 41 carried by the lower end of the toggle linkage 18. The toggle linkage 18 includes a central pin 42, secured to one of the links and supporting the other link. As best seen in FIG. 2, the upper link comprises a pair of spaced links 43, 44, while the lower link comprises a pair of laterally spaced links 45, 46. A bearing 47 is provided at each end of the upper pin 40 which is centrally enclosed by a housing 48. In this embodiment, a web 49 stiffens the assembly. The lower pin 41 is engaged by a bearing 50, while the central pin 42 is engaged by three bearings, 51, 51, 52, the bearing '52 being disposed in an eye 53 secured by threads to the piston rod 54 of the hydraulic or The hydraulic actuator 19 at its rod end is provided with a trunnion 55 which is pivotally supported on a bracket 56 that is secured by a number of screws 57 to the removable head 14 of the module. As the fluid actuator 19 is reciprocated to the left from the position shown in FIG. 1, the actuator 19 pivots when the links are aligned, the right end as illustrated going slightly up, the actuator going back to the position illustrated when the links have passed a like distance beyond the other side of center.

The switches 20, 21 have actuators and are so disposed that the link 43 operates the switch 21 when the piston rod 54 is retracted, and operates the actuator of the switch 20 when the piston rod 54 is extended. The switches 20, 21 may be of any known type and are adjustable so that the amount of travel of I further pressurized fluid thereto by opening the circuits to a 4- way valve in the fluid system.

As best seen in FIG. 1, the removable upper tool holder 16 has an opening concentric with the die 13 in which there is an insert 58 which is tubular in nature, and within which the hold down member 24 isdisposed. The hold down member 24 is tubular and thus has an external surface that is guided by the insert 58 which is fixed with respect to the frame 11. The hold down member 24 has an annular shoulder at its upper end best seen in FIG. 2 through which there extends a number of screws 59 that are threaded into upwardly directed openings in the removable upper tool holder 16. A number of springs 60 act between the tool holder 16 and the hold down member 24, jointly tending to hold the hold down member 24 in the illustrated elevated position. The hold down member 24 has a lug or ear 61 at its front side and at its rear side which are aligned with the clamping actuators 17. In this embodiment, a pair of spacers 62, 62 is employed to bridge the gap between the ears 61 and the lower end of the pistons 36. The lower end of the pistons 36 thus directly engage the spacers 62 to move the hold down member 24 downwardly against the force of the springs 60 to engage the workpiece 23, thereby clamping it against the die 13. If desired, and as shown, the lower end of the hold down member 24 may be provided with a hardened wear ring 63. When the clamping actuators 17 are retracted by the ram as explained above, the springs 60 restore the hold down member 24 to the position illustrated.

The hold down member 24 has an internal surface which serves to guide the upper tool, in this case, the punch tool 22. The punch tool 22 includes the driver portion 31 described above, a punch body 64, and a punch tip 65. A screw 66 extends through the punch tip 65, through the punch body 64 and into the punch driver 61. Suitable keying is provided to orient the punch tip 65 with respect to the punch body in a known manner about a vertical axis. When the removable upper tool holder has been detached so as to disconnect the positive connection 32, 33 between the punch 22 and the ram 15, there would be a tendency for the punch 22 to fall out downwardly but for the presence of a yieldable support means generally indicated at 67. The punch body 64 is slidably guided at its outer surface by the internal surface of the hold down member 24, and the outer surface of the punch body is undercut to receive a support member 68 which normally rests on a shoulder 69 on the internal surface of the hold down member 24. The support member 68 supports the lower end of the resilient means, here comprising springs 70. The support member 68 and the springs 70 comprise the yieldable support means 67 which further includes a ring 71 through which a number screws 72 pass and are threaded into the punch body 64. Thus the upper ends of the springs 70 act against the punch body while their lower ends act against the support member 68 which projects radially and is supported on the shoulder 69. The strength of the springs 70 is adequate to hold the punch 22 in the illustrated position even though the positive connection 32, 33 may be disconnected. However, the springs 70 are relatively weak and would not serve as stripping devices. During punching, the support member 68 remains stationary relative to the hold down member while the punch 22 is moved downwardly against the force of the springs 70. The resistance to such movement of these springs is negligible.

The fluid actuator 19 is of the double-acting type, and has a typical piston diameter of 6 inches. As described in the aforesaid patent, the fluid actuator 19 and the ram 15 cannot be actuated unless fluid pressure is available to operate the clamping actuators 17.

To operate the punching machine, fluid is delivered to one side of the fluid actuator 19 and to the clamping actuators 17. The clamping actuators 17 each have a typical piston diameter of 2-% inches, and the punch ram 15 and the hold down member 24 move downwardly together. However, it is preferred that the capacities, sizes, restrictions and the like in the fluid system be such that the hold down member 24 clamps against the workpiece 23, before the punch 22 engages the workpiece 23. The system continues to deliver fluid to the fluid actuator 19 to drive it through center and to the other end of its travel as determined by the switch 20 or 21. As the toggle linkage 18 passes center, it begins to retract the ram while fluid pressure is still exerted on the hold down member 24. The pressure in the fluid actuator 19 is substantially the same as that in the clamping actuators 17. If the workpiece produces a heavy drag on the punch 22 and resists being stripped from the punch 22, such condition will cause the pressure to build up in the actuator 19, and will cause a corresponding build-up of fluid pressure in the clamping actuators 17. Such pressure build-up increases until the necessary force is produced to strip the workpiece from the punch. After the stripping has been completed, the cross bar (or ears 22) of the ram 15 engages the abutrnents 38 on the clamping actuators 17 and restores them, retracts them or returns them to the uppermost position, forcing fluid out of the clamping actuators. By this action, the fluid actuator 19 overpowers the fluid actuators 17. When the next punch signal is provided, the fluid system reverses the action of the fluid actuator 19, and the action of the ram 15 and the clamping actuators 17 is the same. Thus, a complete punching cycle with the ram going down and going up is produced by each motion of the fluid actuator 19.

In the event that a conventional upper tool holder is employed in place of the tool holder 16, which does not have the hold down member 24, the downward movement of the clamping actuators 17 is limited by the shoulders 38, and the fluid system otherwise operates in the manner described. In such operation, the press ram 15 stores stripping energy in springs that form part of such other tool assembly in a conventional manner. However, the apparatus disclosed herein is particularly advantageous over such prior apparatus in that much higher holding and stripping forces are developed than can be provided in the same space by such prior structures. By this change of structure, it has been possible to increase tonnage capacities of presses from 30-ton to 75-ton.

Although various minor modifications might be suggested by those versed in the art, it should be understood that we wish to embody within the scope of the patent warranted hereon all such embodiments as reasonably and properly come within the scope of our contribution to the art.

We claim as our invention:

1. A punching machine, comprising in combination:

a. a rigid frame of C-shaped configuration having a lower arm for supporting a fixed die and an upper arm; and

b. a power-head assembly constructed as a module and including 1. a rigid head detachably secured to the end of the upper arm for extending above the die on the lower arm,

2. a ram slidably supported by said head for reciprocating a punch with respect to the die,

3. a toggle linkage pivoted at its upper end on said head,

and pivoted at its lower end on said ram, and

4. a fluid actuator pivotally carried by said head and pivotally connected to the center of said toggle linkage for reciprocably driving said ram.

2. A punching machine according to claim 1, including a number of externally accessible screws by which said head is so secured to said upper arm.

3. A punching machine according to claim 2, including means defining a recess in said head and in said upper arm, and a vertically close fitting key disposed therein.

4. A punching machine according to claim 1, including means defining a recess in said head and in said upper arm, and a vertically close fitting key disposed therein.

5. A punching machine according to claim 4, said key extending substantially coextensively with the horizontally mutual extent of said head and upper arm.

6. A punching machine according to claim 1, including means in the module responsive to the movement of the toggle linkage for determining the length of the actuator stroke. 

1. A punching machine, comprising in combination: a. a rigid frame of C-shaped configuration having a lower arm for supporting a fixed die and an upper arm; and b. a power-head assembly constructed as a module and including
 1. a rigid head detachably secured to the end of the upper arm for extending above the die on the lower arm,
 2. a ram slidably supported by said head for reciprocating a punch with respect to the die,
 3. a toggle linkage pivoted at its upper end on said head, and pivoted at its lower end on said ram, and
 4. a fluid actuator pivotally carried by said head and pivotally connected to the center of said toggle linkage for reciprocably driving said ram.
 2. a ram slidably supported by said head for reciprocating a punch with respect to the die,
 2. A punching machine according to claim 1, including a number of externally accessible screws by which said head is so secured to said upper arm.
 3. A punching machine according to claim 2, including means defining a recess in said head and in said upper arm, and a vertically close fitting key disposed therein.
 3. a toggle linkage pivoted at its upper end on said head, and pivoted at its lower end on said ram, and
 4. a fluid actuator pivotally carried by said head and pivotally connected to the center of said toggle linkage for reciprocably driving said ram.
 4. A punching machine according to claim 1, including means defining a recess in said head and in said upper arm, and a vertically close fitting key disposed therein.
 5. A punching machine according to claim 4, said key extending substantially coextensively with the horizontal mutual extent of said head and upper arm.
 6. A punching machine according to claim 1, including means in the module responsive to the movement of the toggle linkage for determining the length of the actuator stroke. 